About Optics & Photonics TopicsOSA Publishing developed the Optics and Photonics Topics to help organize its diverse content more accurately by topic area. This topic browser contains over 2400 terms and is organized in a three-level hierarchy. Read more.

Topics can be refined further in the search results. The Topic facet will reveal the high-level topics associated with the articles returned in the search results.

Abstract

Sensitivity to disk vibration and large component number, which complicates assembly and optical alignment, are the drawbacks of traditional optical pickup systems. Here, a numerical method of designing a dual-wavelength diffractive objective lens with high numerical aperture for generating arbitrarily discrete, diffractionless beams with extended depth of focus is presented. Simulation and experimental results show that the optimized design provides better resolution, longer depth of focus and higher diffractive efficiency. The proposed design is promising for next-generation optical pickup systems that are more robust to disk vibration and easier to assemble.

Table 3 Simulated average spot-size diameter for the Airy criterion, 1/e2, and full width at half maximum (FWHM), which have continuous phases (CP) and quantization phases (16L and 8L), for designing the dual-wavelength ADDB DOL for the DVD optical pickup head.

Table 2

Specifications of the dual-wavelength ADDB DOL for the objective lens of DVD optical pickup head.

Design parameters

Diameter

Depth-of-focus

Diameter spot-size

Input

Output

650 nm

780 nm

650 nm

780 nm

Design scale

4.20 mm

60 μm

±120 μm

1.20 μm

1.80 μm

1.68–1.92 mm

2.28–2.52 mm

Sampling rings/ points

600

1000

4

4

20

30

Table 3

Simulated average spot-size diameter for the Airy criterion, 1/e2, and full width at half maximum (FWHM), which have continuous phases (CP) and quantization phases (16L and 8L), for designing the dual-wavelength ADDB DOL for the DVD optical pickup head.

λ (μm)

Goal of diameter spot size (Airy) μm

The average of simulation diameter spot size (Airy) μm

The average of simulation diameter spot size (1/e2) μm

The average of simulation diameter spot size (FWHM) μm

CP

16L

8L

CP

16L

8L

CP

16L

8L

0.65

1.20

1.02

1.08

0.96

0.594

0.567

0.57

0.361

0.344

0.33

0.78

1.80

1.59

1.59

1.62

1.072

1.033

1.089

0.611

0.589

0.583

Tables (3)

Table 1

Specifications of the DVD optical pickup head white paper.

Specifications

DVD-ROM

CD-ROM

Laser wavelength (nm)

650

780

Track distance (μm)

0.74

1.6

Pit depth (μm)

0.12

0.11

Pit length (μm)

0.4

0.834

Pit width (μm)

0.32

0.6

Numerical aperture (N.A.)

0.6

0.45

Diameter spot-size (μm)

1.32

2.11

Table 2

Specifications of the dual-wavelength ADDB DOL for the objective lens of DVD optical pickup head.

Design parameters

Diameter

Depth-of-focus

Diameter spot-size

Input

Output

650 nm

780 nm

650 nm

780 nm

Design scale

4.20 mm

60 μm

±120 μm

1.20 μm

1.80 μm

1.68–1.92 mm

2.28–2.52 mm

Sampling rings/ points

600

1000

4

4

20

30

Table 3

Simulated average spot-size diameter for the Airy criterion, 1/e2, and full width at half maximum (FWHM), which have continuous phases (CP) and quantization phases (16L and 8L), for designing the dual-wavelength ADDB DOL for the DVD optical pickup head.